The shared backup reader kept documents without their stored bytes but
kept every ECG strip whole, trace included. A long watch history is
hundreds of strips of tens to hundreds of kilobytes each, so an upload,
preview or restore of such a copy held the whole history in memory.
The first read now keeps each strip without its trace (a short stand-in,
after the key it was written under is recorded and its form checked),
and forEachEcgTrace reads the traces again one strip at a time. The ECG
restore writes each strip from that second read, as the document restore
already did, and refuses a file whose two reads disagree on the count.
The upload memory test gains an ECG-heavy file: 150 strips, about 200 MB.
The old reader held 197 MB of it and failed the 48 MB bound; the new one
holds about 1 MB, also under a 524 MB heap.
The admin upload streamed only the measurements while it checked a file,
so a document-heavy account copy was held whole in memory and an upload of
a few hundred megabytes could take the process down.
The sections a reader takes an element at a time are now named once
(BACKUP_STREAMED_SECTIONS in streamed-backup.ts): measurements, intake
events, mood entries, documents and ECG recordings. The upload reads its
file through readStreamedBackup like the restore and the preview, and the
restore drill and the restore script use the same key set.
A behavioural test pushes a 271 MB document-heavy file through the real
upload route and fails when the heap grows with the file. The stream guard
now asserts that every reader goes through the shared reader or key set
and that no file declares its own.
Marc-André Bombeck